package main.java.indi.zyj.interview;

public class AddStrings {

    public static void main(String[] args) {

    }

    public String addStrings(String num1, String num2) {
        // 123 123
        int i = num1.length() - 1, j = num2.length() - 1, add = 0;

        StringBuffer ans = new StringBuffer();

        while (i >= 0 || j >= 0 || add != 0) {


            int x = i >= 0 ? num1.charAt(i) - '0' : 0;
            int y = j >= 0 ? num2.charAt(j) - '0' : 0;
            int result = x + y + add;
            ans.append(result % 10);
            add = result / 10;
            i--;
            j--;

        }

        // 计算完以后的答案需要翻转过来
        ans.reverse();
        return ans.toString();
    }

}
